C/2021 F1 (Lemmon-PANSTARRS)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Nearest approach	12 Feb 2022	10.9	1.335 AU	1.416 AU	20h29m	+48°54'	64.7°	41.9°	340°
Perihelion	6 Apr 2022	9.6	0.999 AU	1.904 AU	01h06m	+24°18'	17.8°	17.8°	5°
Today	18 Sep 2026	31.2	14.184 AU	14.487 AU	12h26m	-68°19'	70.5°	3.8°	169°

The interactive orbit chart above shows the comet's path through the solar system and its position at the given date. Green and blue lines are shown perpendicular to the ecliptic plane: Green if the path is above the ecliptic plane, blue if it is below. (Left-click and drag to rotate the view; Right-click and drag to move the view; Use scroll wheel to zoom in our out.)

Light curve

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations from COBS. This lightcurve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 8.3 + 5 log[∆] + 14.9 log[r]). An additional green curve is displayed when an increase in apparent brightness is expected due to forward scattering of sunlight, which occurs when a dust-rich comet is located between the Earth and the Sun. (See Marcus 2007)

Charts

The all-sky chart below shows the path of the comet over the same period as the light curve. The comet's current position is marked yellow.

The following chart shows the short-term path of the comet in a field of view that is optimized for (~10x50) binoculars and finderscopes.

Orbital elements

The orbital elements of C/2021 F1 (Lemmon-PANSTARRS) are:

    e (Eccentricity)                : 0.9958570
    q (Perihelion distance)         : 0.9994680
    i (Inclination)                 : 107.25990
    Ω (Longitude of ascending node) : 203.62630
    ω (Argument of perihelion)      : 146.97410
    L (Longitude of perihelion)     : 214.54313
    B (Latitude of perihelion)      : 31.36413
    T (Time of perihelion passage)  : 2459676.27770
    P (Orbital period in years)     : 3746.98

    Epoch                           : 2026 May 29
    Reference                       : MPC194173

    Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); External (P > 200 years)

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-09-17 00:00 UT   12 24 58.7   -68 19 56    14.463   14.173   71.3    3.9   167   31.2 
2026-09-18 00:00 UT   12 25 39.8   -68 19 32    14.477   14.179   70.8    3.8   168   31.2 
2026-09-18 17:52 UT   12 26 10.5   -68 19 17    14.487   14.184   70.5    3.8   169   31.2 
2026-09-19 00:00 UT   12 26 21.0   -68 19 12    14.490   14.185   70.4    3.8   169   31.2 
2026-09-20 00:00 UT   12 27 02.2   -68 18 54    14.504   14.191   70.0    3.8   170   31.2 
2026-09-21 00:00 UT   12 27 43.4   -68 18 41    14.517   14.198   69.5    3.8   170   31.2 
2026-09-22 00:00 UT   12 28 24.7   -68 18 30    14.531   14.204   69.1    3.8   171   31.2 
2026-09-23 00:00 UT   12 29 05.9   -68 18 22    14.544   14.210   68.7    3.8   172   31.2 
2026-09-24 00:00 UT   12 29 47.2   -68 18 18    14.557   14.216   68.2    3.8   173   31.2 
2026-09-25 00:00 UT   12 30 28.5   -68 18 17    14.570   14.222   67.8    3.7   173   31.2 
2026-09-26 00:00 UT   12 31 09.8   -68 18 19    14.583   14.228   67.4    3.7   174   31.2 
2026-09-27 00:00 UT   12 31 51.2   -68 18 24    14.596   14.234   67.0    3.7   175   31.2 
2026-09-28 00:00 UT   12 32 32.5   -68 18 32    14.609   14.240   66.6    3.7   176   31.2 

    Terminology:
            
    delta:  distance between comet and earth in AU
    radius: distance between comet and sun in AU
    magn:   magnitude (brightness) estimate    
    ra:     right ascension in hours (24h = 360deg)
    dec:    declination in degrees
    elong:  elongation in degrees (angle sun-earth-comet)    
    phase:  phase angle in degrees (angle sun-comet-earth)        
    AU:     Astronomical Unit (mean distance between earth and sun: 149597870.7 km      
    

Orbital elements usually provided by the MPC (Minor Planet Center).
Observations contributed by observers worldwide, via COBS (Comet Observation Database) or the MPC (Minor Planet Center)
Calculations by a modified version of AAPlus, a C# implementation of the AA+ project by PJ Naughter from the algorithms presented in the book "Astronomical Algorithms" by Jean Meeus.
NGC2000 dso catalog and star labels from VizieR as provided by the Strasbourg astronomical Data Center.
Tycho2 catalog from the ESO archive.